How large will federal deficits grow over the next decade?
Core argument: CBO projects the federal deficit at $1.9 trillion in fiscal 2025, or 6.2% of GDP, growing to $2.7 trillion by 2035, when the adjusted deficit equals 6.1% of GDP, compared with the 3.8% average of the past 50 years.
In CBO’s baseline projections, the federal budget deficit in fiscal year 2025 is $1.9T. The deficit grows to $2.7 trillion by 2035. It amounts to 6.2% of GDP in 2025 and drops to 5.2% by 2027 as revenues increase faster than outlays. In later years, outlays increase faster than revenues, on average. In 2035, the adjusted deficit equals 6.1% of GDP—significantly more than the 3.8% that deficits have averaged over the past 50 years. Federal outlays in 2025 total $7T, or 23.3% of GDP. They remain close to that level through 2028 and then rise, reaching 24.4% of GDP in 2035. The main reasons for that increase are growth in spending for Social Security and Medicare and rising net interest costs. Revenues total $5.2T, or 17.1% of GDP, in 2025. They rise to 18.2% of GDP by 2027, in part because of the scheduled expiration of provisions of the 2017 tax act. Revenues decline as a share of GDP over the next two years, falling to 17.9% in 2029, but then generally increase, reaching 18.3% in 2035.

